Zephyrproject: >> Zephyr >> 4.4.0 Security Vulnerabilities
The native BSD-socket layer recorded a pending asynchronous socket error by type-punning it into struct net_context's void user_data field (ctx->user_data = INT_TO_POINTER(-status) in zsock_accepted_cb(), zsock_received_cb(), zsock_connected_cb() and zsock_close_ctx() in subsys/net/lib/sockets/sockets_inet.c), reading it back with POINTER_TO_INT(). That same field is owned by the network stack for listening TCP contexts: net_tcp_accept() stores the parent context pointer there and the TCP core passes it back to the registered accept callback. A failed accept therefore left a small integer (an errno value) where the stack expected a struct net_context .
When the network interface carrying a listening TCP socket goes down, close_tcp_conn() in subsys/net/ip/tcp.c invokes the accept callback with -ENETDOWN and the context's user_data. In v4.3.0 the callback was not disarmed afterwards, so a second interface-down event forwarded the previously stored errno to zsock_accepted_cb(), which dereferenced it as the parent context and performed several stores through it (sock_set_error()'s read-modify-write of socket_data, k_fifo_cancel_wait(&parent->recv_q)) — the crash described in the fix's commit message. v4.3.1 and v4.4.x carry a later change clearing conn->accept_cb after the error callback (269cb8823d3 on the v4.3 branch, 913fae5169425550f2364655298fceb79b320066 on main), which closes that repeat path; on those releases the poisoned cookie remains reachable only by a narrower race, a handshake completing alongside the interface-down still passing the stale cookie to k_fifo_put(&parent->accept_q, ...), and by getsockopt(SO_ERROR), which reads the field back unconditionally.
On v4.3.0 an application that keeps a listening TCP socket open across repeated link-down events is sufficient to reach the defect; the triggering condition is a network-interface state change, not attacker-supplied packet data, so the practical attacker is one able to force the link down repeatedly (for example an adjacent attacker disrupting a wireless link) or one with local/physical access. Because both the faulting address and the stored data are fixed small constants derived from the errno value, the outcome is a wild-pointer access leading to a kernel fatal error — a denial of service (device crash or reset) rather than an attacker-directed memory corruption.
The fix stores the pending error in a dedicated net_context.sock_error field and converts every producer and consumer to sock_set_error()/sock_get_error(), leaving user_data untouched. As a side effect it also stops getsockopt(SO_ERROR) — which is evaluated unconditionally — from returning the kernel address held in user_data to a userspace application.
CVSS Score
6.5
EPSS Score
0.002
Published
2026-09-29
parse_write_op() in subsys/net/lib/lwm2m/lwm2m_message_handling.c handles inbound CoAP WRITE/CREATE requests that carry a Block1 option. For the first block of a transfer it called init_block_ctx() and then immediately stored the peer-selected block size with block_ctx->ctx.block_size = block_size before inspecting the return code. init_block_ctx() sets the caller's pointer to NULL and returns -ENOMEM when no entry of the static block1_contexts[] pool is free or timed out, so that store dereferences a NULL pointer.
The pool holds CONFIG_LWM2M_NUM_BLOCK1_CONTEXT entries (default 3) and an entry is only reclaimed once its transfer completes, fails, or ages past 30 seconds. A peer that reaches the client's LwM2M socket can therefore start three block-wise writes on three distinct object paths with the CoAP More bit set and leave them incomplete, then send the first block of a fourth write on a new path to reach the unguarded dereference. Reachability is gated only by the connected UDP socket's source-address filter unless CONFIG_LWM2M_DTLS_SUPPORT is enabled — which has no default — so in a NoSec deployment an on-path or address-spoofing attacker needs no credentials; the same sequence is also reachable from a bootstrap or lower-trust server, and can be hit accidentally by a legitimate server running four concurrent block transfers.
The write targets a fixed low address with a value between 0 and 7, so the consequence is a fatal memory fault (BusFault or corrupted low memory leading to a fault) rather than a usable memory-corruption primitive: the device crashes or resets. Confidentiality and integrity are not affected. The fix moves the store below the guard and validates the context pointer itself instead of the return code, so the context is only touched once it is known to be valid.
CVSS Score
5.9
EPSS Score
0.003
Published
2026-09-29
The MCUmgr SMP-over-console transport decodes a base64 frame, reads a 16-bit packet length from it, verifies a CRC and then unconditionally strips the trailing CRC with rx_ctxt->nb->len -= 2U; in mcumgr_serial_process_frag() (subsys/mgmt/mcumgr/transport/src/serial_util.c). mcumgr_serial_extract_len() accepted any declared length, including 0 and 1, and a packet declaring length 0 passes the checksum test for free because crc16_itu_t() over zero bytes returns the zero seed. Since net_buf::len is a uint16_t, the subtraction underflows and the buffer is handed to SMP claiming roughly 65 KB of payload while its data area is only CONFIG_MCUMGR_TRANSPORT_NETBUF_SIZE bytes (default 384).
The trigger is a single unauthenticated 7-byte line on the management console — the 0x06 0x09 packet marker followed by the base64 group AAA= and a newline — delivered to any transport built on this helper: CONFIG_MCUMGR_TRANSPORT_UART (smp_uart.c) or CONFIG_MCUMGR_TRANSPORT_SHELL (smp_shell.c), both of which select MCUMGR_TRANSPORT_SERIAL_HAS_SMP_OVER_CONSOLE. No prior session state, fragmentation or credentials are required to trigger the underflow, and the malformed frame is mishandled before any command handler or command-level access control runs. The attacker only needs write access to that console, which on many boards is a USB CDC-ACM port rather than a bare UART header.
With the inflated length, smp_process_request_packet() in subsys/mgmt/mcumgr/smp/src/smp.c loses its bound: cbor_nb_reader_init() gives the CBOR decoder a ~65 KB window into a 384-byte buffer, and each request header's nh_len is checked only against the inflated length. On its own the 7-byte frame re-parses whatever stale bytes the reused pool buffer still holds, typically a replay of the previously received request followed by a parse error, without leaving the buffer. Because the transport is unauthenticated, though, the attacker also controls the frames sent before the trigger, and can stage buffer contents so that a request succeeds with an nh_len larger than the buffer; net_buf_pull(), guarded only by __ASSERT_NO_MSG, then moves the parse cursor out of bounds and the loop reads further headers and CBOR from adjacent memory. The consequence is an out-of-bounds read that can fault the MCUmgr thread (denial of service); memory disclosure is also possible, since the default-enabled os echo handler (CONFIG_MCUMGR_GRP_OS_ECHO) decodes its string inside that window and copies it into its response. There is no integrity gain beyond what the unauthenticated transport already permits.
The fix rejects any declared packet length of two bytes or fewer in mcumgr_serial_extract_len(), so the CRC-strip subtraction can no longer underflow. The identical pattern remains in the test-only loopback transport subsys/mgmt/mcumgr/transport/src/smp_dummy.c (CONFIG_MCUMGR_TRANSPORT_DUMMY), which has no external input path and therefore carries no practical exposure.
CVSS Score
6.8
EPSS Score
0.002
Published
2026-09-29
The ADC API requires each driver to reject a sampling sequence whose destination buffer is too small: the buffer_size field of struct adc_sequence in include/zephyr/drivers/adc.h documents that "the driver must ensure that samples are not written beyond the limit and it must return an error if the buffer turns out to be not large enough". The ADI MAX32 driver did not honour that contract. start_read() in drivers/adc/adc_max32.c compared buffer_size, a byte count, against a sample count ((1 + extra_samplings) channels), ignoring sizeof(uint16_t), so it accepted a buffer half the required size. The samples are then stored through the uint16_t data->buffer by Wrap_MXC_ADC_GetData(), which writes two bytes per sample and advances the pointer by one uint16_t: in adc_max32_start_channel() for synchronous reads, and in adc_max32_isr() for asynchronous ones. A sequence selecting two channels with a two-byte buffer, for example, passes the check and has its second sample written past the end of the buffer.
On a build with CONFIG_USERSPACE, adc_read() and adc_read_async() are system calls. The handler in drivers/adc/adc_handlers.c copies the sequence in from user memory, verifies only that [buffer, buffer + buffer_size) is writable by the calling thread, and rejects a user-supplied options->callback; it deliberately leaves the size arithmetic to the driver. A user-mode thread that has been granted access to a MAX32 ADC device object therefore fully controls channels, buffer, buffer_size and options->extra_samplings, and can make the driver write twice as many bytes as its buffer holds. Because the check scales with extra_samplings, the overrun equals the length of the buffer itself, up to channels * 65536 bytes past its end, since the sample pointer is only rewound on a repeat sampling, never on the extra samplings of a sequence.
The resulting stores are performed by the driver in kernel mode (in the system call itself, the ADC context timer, or the ADC interrupt handler for asynchronous reads), where the MPU does not restrict the thread's memory domain, so the write walks linearly out of the user partition and into adjacent memory such as other partitions, kernel data or thread stacks. The impact is kernel-memory corruption of attacker-chosen length at an attacker-chosen offset, a plausible privilege-escalation and denial-of-service primitive from an unprivileged user-mode thread. Builds without CONFIG_USERSPACE are affected only as a caller-side robustness defect, since the application itself supplies the buffer.
The fix replaces that check in start_read() with a call to the new shared helper adc_sequence_validate_buffer() in drivers/adc/adc_common.c, passing sizeof(uint16_t) as the sample size. The helper computes active_channels sizeof(uint16_t) (1 + extra_samplings) and returns -ENOMEM before any sampling is started.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-09-28
ieee802154_send() in subsys/net/l2/ieee802154/ieee802154.c copies the outgoing packet into a single fixed 125-byte transmit buffer (tx_frame_buf_pool, sized IEEE802154_MTU). In builds with CONFIG_NET_L2_IEEE802154_FRAGMENT enabled (the default whenever CONFIG_NET_6LO is set), the branch taken when 6LoWPAN fragmentation is not required performed an unchecked net_buf_add_mem(frame_buf, pkt_buf->data, pkt_buf->len). The only guard was __ASSERT_NO_MSG() inside net_buf_simple_add(), which is compiled out without CONFIG_ASSERT, so an oversized packet silently overran the frame buffer.
The defect is not reachable from the radio: for NET_AF_INET6 packets ieee802154_6lo_encode_pkt() compares the whole packet length against IEEE802154_MTU and takes the fragmentation path when it does not fit, so every buffer copied on the unfragmented branch is within bounds. It is reachable through NET_AF_PACKET sockets bound to an 802.15.4 interface: for NET_SOCK_RAW the 6LoWPAN block is skipped entirely and for NET_SOCK_DGRAM it returns early on the address-family test, leaving no length validation anywhere on the transmit path (net_context_sendto() and net_if_tx() apply none, and pkt_buffer_length() does not clamp the allocation for this L2).
An application — or, in a CONFIG_USERSPACE build, an unprivileged application thread using the zsock_socket()/zsock_sendto() syscalls — can therefore drive a supervisor-mode out-of-bounds write of chosen bytes past the 125-byte pool buffer. With the default CONFIG_NET_BUF_FIXED_DATA_SIZE of 128 bytes the overrun is bounded to roughly ll_hdr_len + 3 bytes; with CONFIG_NET_BUF_VARIABLE_DATA_SIZE a single storage buffer can be as large as CONFIG_NET_PKT_BUF_TX_DATA_POOL_SIZE, making the overrun far larger. The consequence is corruption of memory adjacent to the pool, with a crash or further compromise of kernel state as the practical impact.
The fix validates ll_hdr_len + net_pkt_get_len(pkt) + authtag_len against IEEE802154_MTU before any copy and adds a tailroom-checking copy_pkt_to_frame() helper that returns -EMSGSIZE instead of overrunning the buffer. The same change also linearizes the whole net_buf chain into one MAC frame, so packet storage boundaries no longer become frame boundaries on the wire.
CVSS Score
6.3
EPSS Score
0.001
Published
2026-09-28
The CoAP link-format helper match_path_uri() in subsys/net/lib/coap/coap_link_format.c compares a registered resource path against the URI carried in a Uri-Query href= option. That URI is not NUL terminated, but the inner character loop advanced its index k once per path character without ever testing it against the option length len. When a registered path segment is longer than the supplied URI and the URI is a prefix of it, the loop reads uri[len] and beyond, past the end of the option value.
The path is reached from coap_well_known_core_get_len() and coap_well_known_core_get() via match_queries_resource(), i.e. by any unauthenticated GET /.well-known/core?href=/<prefix> request to a device that serves /.well-known/core (for the CoAP server subsystem, CONFIG_COAP_SERVER_WELL_KNOWN_CORE, default y) and has at least one resource that declares struct coap_core_metadata attributes.
The over-read does not reach the receive buffer. The well-known-core builders parse the query into a stack-local struct coap_option, whose value is a fixed array (value[12], or CONFIG_COAP_EXTENDED_OPTIONS_LEN_VALUE bytes) that the option bytes are copied into, so uri points into that copy. Reading past len therefore reads the unused, uninitialized tail of the array and, when the option fills it, the bytes just past it in the same stack frame. (In the ZoAP library of v1.8.0 to v1.9.x the option value was instead a pointer into the received packet, and the over-read ran past the option inside the packet buffer.)
The impact is bounded. The number of bytes read past the end is limited by the length of the resource path segment, and each additional byte is only read if it happens to equal the next path character, so in practice the over-read is one byte. It also cannot influence the response: returning a match requires the final compared index to be len - 1 or len, both in bounds, so out-of-bounds bytes only ever steer the loop to the next candidate resource. The consequence is undefined behaviour, not information disclosure and not a matching error.
The fix adds a k >= len guard at the top of the inner loop, so every uri[k] dereference is within the option value while still allowing a trailing * wildcard to match a longer path.
CVSS Score
3.7
EPSS Score
0.002
Published
2026-09-28
The LoRaWAN application-layer clock-synchronization service parses downlinks in clock_sync_package_callback() (subsys/lorawan/services/clock_sync.c). Its command loop only guarantees that the one-byte command id is in bounds; for the CLOCK_SYNC_CMD_APP_TIME (AppTimeAns) command the handler then reads a 4-byte time correction via sys_get_le32() plus a 1-byte token without checking that 5 bytes remain in the receive buffer (len - rx_pos). A short or crafted AppTimeAns therefore reads up to 5 bytes past the end of the decrypted payload.
The payload (rx_buf/len) is the decrypted application frame delivered to the registered downlink callback (mcps_indication->Buffer/BufferSize). Reaching the handler requires a frame on the clock-sync port that passes LoRaWAN's MAC integrity check and FRMPayload decryption, so the practical attacker is a malicious or compromised network/application server (the designated sender of AppTimeAns) or a party holding the session keys, rather than an arbitrary radio listener.
The over-read is bounded: the backing store is a fixed 255-byte static buffer, so the few stray bytes do not fault, and the read values (time_correction, token) are used only internally and never transmitted, so there is no disclosure to the attacker and no crash. The sole effect is that a stale token matching ctx.req_token can apply a garbage time_correction to the device's own clock offset (ctx.time_offset), a minor integrity impact confined to the victim's time estimate. The fix adds an explicit length check that drops a too-short AppTimeAns. Note the sibling one-byte reads in the periodicity and force-resync handlers remain unguarded with the same negligible impact.
CVSS Score
3.1
EPSS Score
0.002
Published
2026-08-26
The LoRaWAN TS004 Fragmented Data Block Transport handler frag_transport_package_callback() in subsys/lorawan/services/frag_transport.c parses downlink command bytes without validating that enough payload bytes remain before each access. The loop's only bound is rx_pos < len; after consuming the one-byte command id the handler cast rx_buf + rx_pos to a 10-byte struct frag_transport_setup_req, and for a DATA_FRAGMENT command passed &rx_buf[rx_pos] to the fragment decoder, which reads exactly ctx.frag_size bytes — with no remaining-length check in either case.
The fragment size is attacker-chosen in a preceding FRAG_SESSION_SETUP command (ctx.frag_size = req->frag_size, capped at CONFIG_LORAWAN_FRAG_TRANSPORT_MAX_FRAG_SIZE, default 232). rx_buf aliases the 255-byte static MacCtx.RxPayload buffer in the loramac-node MAC layer, while len is the actual decrypted payload length. By padding a downlink with mismatched-index DATA_FRAGMENT filler commands (each advancing rx_pos by three bytes without producing an answer) and appending one matching-index fragment near the end of the payload, an attacker can make the decoder read up to roughly frag_size bytes past the end of RxPayload, copying adjacent static memory into the decoder buffers and the FUOTA flash image.
The handler runs only on downlinks that have already passed the LoRaWAN frame MIC and FRMPayload decryption, so the defect is reachable only by a party holding the device's session keys (the FUOTA server or an attacker who has compromised those keys). The out-of-bounds bytes are never returned to the sender — the only uplink emitted is a status answer carrying fragment counts — so there is no direct disclosure channel, and on typical flat-memory LoRaWAN MCUs the over-read stays within mapped memory, making a crash unlikely. The impact is therefore a bounded out-of-bounds read with limited confidentiality consequence and no write or control-flow primitive. The fix adds remaining-length guards before each access.
CVSS Score
3.1
EPSS Score
0.002
Published
2026-08-26
The IEEE 1588 PTP management-message parser in subsys/net/lib/ptp/tlv.c mishandles the PTP_MGMT_TIME management id. In tlv_mgmt_post_recv(), the PTP_MGMT_TIME case casts mgmt_tlv->data to a 10-byte struct ptp_timestamp and reads it (then byte-swaps and writes it back) without first checking that the TLV data field is at least sizeof(struct ptp_timestamp). Every sibling management id in the same switch validates its length first; PTP_MGMT_TIME was the only case lacking that check.
The length passed in is the management data size (tlv->length - 2), and the upstream guard in ptp_tlv_post_recv() only requires tlv->length > 2, while msg_tlv_post_recv() validates only that the TLV fits within the received byte count, not a per-id minimum. A peer on the local PTP segment can therefore send a PTP_MSG_MANAGEMENT message carrying a short PTP_MGMT_TIME TLV (data as small as 2 bytes), causing the parser to read and write 8 bytes beyond the validated data. The message type and TLV contents are taken straight off the wire, so the path is reachable by any adjacent attacker when CONFIG_PTP is enabled.
The over-read and write-back stay within the struct ptp_msg allocation (mgmt_tlv->data lives in the leading mtu[NET_ETH_MTU] union member, so data + 10 lands at most a few bytes past mtu[], inside the same object), so this is an out-of-bounds read of adjacent in-object memory plus a bounded in-place corruption of the message's parsed timestamp, not past-allocation memory corruption. Impact is limited to minor information exposure of adjacent bytes and corruption of the device's parsed management TIME value; there is no crash on the access and no reachable reference-count corruption.
The fix adds if (length < sizeof(struct ptp_timestamp)) { return -EBADMSG; } before the cast, matching the other management-id cases and fully closing the receive-path defect.
CVSS Score
5.4
EPSS Score
0.002
Published
2026-08-26
The Bluetooth host ATT layer (subsys/bluetooth/host/att.c) associates each in-flight ATT TX buffer with its owning channel via the static tx_meta_data_storage[] array (data->att_chan = chan). When a buffer's last reference is dropped, its net-buf destroy callback defers the completion handling to the system workqueue (att_tx_destroy -> att_tx_destroy_work_handler -> att_on_sent_cb -> bt_att_sent), where bt_att_sent dereferences the channel and its ATT context (sys_slist_get(&att->reqs)).
When a peer disconnects while an ATT PDU (a server notification/indication or any response) is still in flight in the controller TX path, L2CAP tears the channel down in l2cap_chan_del(): it runs the disconnected callback and then the released callback (bt_att_released), which frees the channel slab slot. Because the in-flight buffer is held by the connection TX path rather than the channel's own queue, its deferred destroy work can run after the channel has been freed. The att_on_sent_cb guard intended to drop the stale callback itself dereferences meta->att_chan, which is now a dangling pointer into a freed (and possibly reused) slab slot.
A remote peer with an ATT connection can drive this by disconnecting during routine ATT traffic; no pairing or user interaction is required to reach the ATT bearer. The result is a use-after-free read/write of freed channel memory, reliably crashing the Bluetooth host (denial of service) and, because the channel slab slot may be reused, potentially corrupting live memory.
The fix makes bt_att_released() NULL the att_chan field of every tx_meta_data_storage[] entry still referencing the channel before freeing it, so the deferred guard observes a NULL pointer and drops the callback. Teardown and the destroy work both run on the cooperative system workqueue, so the array update is serialized and needs no lock.
CVSS Score
7.1
EPSS Score
0.003
Published
2026-08-04
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